ESXi hosts out of sync on a vDS after migration/upgrade

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

In vCenter > Networking > vDS > Summary, you see the warning: 
"The vSphere Distributed Switch configuration on some hosts differed from that of the vCenter Server."
 
ESXi log File Path: /var/run/log/
In hostd.log, you see "file not accessible" messages ("skip saving dvport" is not important by itself): 
2020-09-24T13:57:34.446Z warning hostd[2100489] [Originator@6876 sub=Hostsvc.NetworkProvider opID=########-15c1 user=vpxuser] Skip saving dvport ######### to /vmfs/volumes/#####-########-####-##########/.dvsData/## ## ## ## ## 8a 56 69-1a c0 56 2e 2c 7a e8 e0/401: file not accessible

Some VM's may lose connectivity after being migrated from a host with a cswitch (6.6) proxy vDS to a host with an etherswitch (6.5 and below) proxy vDS.

Environment

VMware vCenter Server 6.7
VMware vCenter Server 7.0
VMware vCenter Server 8.0

Cause

This scenario can happen if there is a pending vDS 6.6 upgrade that cannot be completed due to the out of sync dvPorts.

Resolution

Please file a Support Request and mention this article.
Upload the log bundle of vCenter and the ESXi

Additional Information

If your logs do not show "file not accessible", please see ESXi hosts showing out of sync with distributed switch.